I like the idea of being able to have renewable power as this would be the goal in a apocalypse-type situation, fossil fuel isn't going to be easy to fine and eventually it WILL run out (no oil refineries producing the fuel) so the only other option would be to go the renewable energy route. One of the goals of surviving is to be as self sufficient as possible and that means having renewable sources of water, food and power.
If there are solar panels there shouldn't be a limit to how many you can chain together or make because that wouldn't be the slightest bit realistic, tho the panels or the materials used to make the panels should be either ultra rare and/or in locations that are very dangerous to venture into alone (encourages teamwork).
Now if you don't want to go the solar panel route and want to make renewable energy and to make it in such a way as to have some effort in creating the power you could always look into adding something called a wood gasifier like this:
Here's a poor man's (beginner's) build of a wood gasifier (the fellow has a speech impediment so be patient):
Here's a video showing instructions on how to build a wood gasifier (pardon the religious nutcase, filter out the crap and it's a good video. ):
Simple(ish) to make and use but requires you to always have a supply of wood for fuel (and a lot more realistic then having an infinite supply of petroleum based fuel in game).
That's my thoughts on it, might be feasible, might not be...
Hydro Power - this always seems to be forgotten. i think, that when others think of 'hydro electric power', they imagine the hoover dam, or huge turbines in the ocean ..... and every one forgets the water wheel ..... simple, eloquent, quite sexy looking.
this one is not so sexy ..... but BOOM for the power it puts out
I have seen some little windmills on the odd small farm in the test area, I have no idea if they could create enough energy to draw power mind you also there could be larger ones added and depending on some neighbourhoods economical class there could be a house or two that has solar panels... this is one of those ideas that people would do after some time, so I'd like this for after you/others have used up all other resources for power.
I think that having Solar Panels wouldn’t be OP. Unless you have a battery (which are a little hard to get), you will only have power during the day. Also, i have seen solar panels at a cabin irl where the solar panels are not on the roof. They were only two on a pole to the side of the house and with only lights on, the house generator (one with automatic start/stop for charging the battery, no human interaction needed) would turn on multiple times during the night to recharge the batteries. It would stay on for like 30 mins or so. So, if we took that model to in-game time, that would only be 30s to 1 min. Obviously, in-game you will need to find each and every battery cell (well, complete battery packs, which may include a few cells) just like other parts in-game, and so you would slowly build up your battery power and with decay due to use, it will not be OP. I think that decay time, with regular use, should be like 50% of life decay for batteries.
Edit: changed Would to wouldn’t. I know the following sentence addresses how to make them not be OP, but I want solar panels in-game, not to mention, I think the devs are good at fleshing things out in a mostly realistic/ intuitive way and would come up with a good system that’s balanced. Honestly, I just want to be able to run things during the day on solar (in-game) so that I can save my generator fuel for the night